As a result of prolonged usage of flexible heating elements, it sometimes occurs that a particular element fails and needs to be replaced or repaired. In instances where the flexible heating element is secured by cement or adhesives directly to the item to be heated, the removal of the heater often requires a great deal of manual labor and may result in destruction of the heater. Where the heater is mechanically secured directly to the item by clamps or the like, removal of the heater generally requires disassembly of the entire heater-mechanical connection assembly in order to replace or repair the failed element. Another disadvantage of mechanical connecting systems is that they often consist of multiple parts requiring high replacement inventory and, dependent upon their particular design, are often difficult to assembly and disassemble. A further disadvantage of both cementing or adhesively or mechanically securing the heating element directly to the item is that such systems require complete disassembly in order to change the heating capacity of the element if such is required. Other disadvantages of such systems designed to either adhesively or mechanically secure a heating element directly to the item to be heated is that they in many cases do not themselves provide a means of thermally insulating the heating element so as to enhance the element's heating efficiency and often such systems are unable to adapt to irregular shaped surfaces.
Examples of the heaters of the type heretofore described that are designed to be directly secured to the items to be heated by adhesives can be found, for example, in U.S. Pat. Nos. 2,669,646; 3,757,087; and 4,058,704. Examples of heaters of the type heretofore described as secured directly to the item by means of mechanical connectors can be found in U.S. Pat. Nos. 3,257,498; 3,398,262; and 3,971,416.
In contrast to past practice, the present invention provides an elongate flexible packaged enclosure for containing an elongate electrical heating element that is designed to enhance the thermal heating efficiency of the electrical heater and permit the heating element to be axially removed from and inserted into the package for replacement and repair without having to remove the package from the item to which it is secured.